Deletion or silencing of tumor suppressor genes (TSG) through genetic or epigenetic events has been found to play an important role in the development of different cancers. Early studies suggest that frequent silencing of TSG through promoter hypermethylation in bladder Urothelial Cell Carcinomas (UCC) represent novel diagnostic and therapeutic targets. Here we propose to further elucidate the bladder cancer methylome and thereby identify novel methylated genes as markers for early detection, prognostic classification, and predictive classification of response to therapy of urothelial cell carcinoma of the bladder (UCC). Since we have reported a role for methylated genes in the development of cisplatin resistance, we will also identify genes that are related to cisplatin response and silenced by promoter hypermethylation in UCC. We are proposing three specific aims: In Specific Aim 1, an integrated screening approach will be undertaken to further identify novel tumor-specific genes silenced by promoter hypermethylation in 5 UCC cell lines. Specific Aim 2 We will test multiple promoter hypermethylation markers for UCC in various tissues and bodily fluids from patients with and without disease to establish simple sensitivity and specificity estimates. Finally, in Specific Aim 3 we will examine the functional significance and clinical relevance of the novel genes in primary tumors for future prevention approaches. A comprehensive approach consisting of expression array hybridization and pharmacological unmasking strategies, and the Infinium Methylation Assay will be taken to identify common epigenetic alterations in bladder tumor evolution. In vitro and in vivo characterization of identified genes which are inactivated by promoter hypermethylation will help us understand their impact on UCC development, role in cancer progression and biological role in drug resistance. Ultimately, identified bladder cancer specific methylation markers will be used as markers for non-invasive molecular detection approaches, prognostic markers for PT1 tumors, determination of platinum response and as novel targets for therapeutic prevention.